Terminal for mercury-vapor apparatus.



F. G. KEYES.

TERMINAL FOR MERCURY VAPOR APPARATUS.

APPLICATION FILED JAN.8. I914. RENEWED MAY II I915.

1,158,928. Patented Nov. 2, 1915.

WITNESSES UNITED STATES PATENT OFFICE.

FREDERICK G. KEYES, OF EAST ORANGE,

NEW JERSEY, ASSIGNOR TO COOPER HEWITT ELECTRIC COMPANY, OF HOEOKEN, NEW JERSEY, A CORPORATION OF NEW JERSEY.

TERMINAL FOR MERCURY-VAPOR APPARATUS.

Application filed January 8. 1914, Serial No. 811,001.

To all whom it may concern: 1

Be it known that I, FREDERICK G. KEYns, a citizen of the United States, and resident of East Orange, county of Essex, State of New Jersey, have invented certain new and useful Improvements in Terminals for Mercury-Vapor Apparatus, of which the following is a specification.

The improvements described herein relate to a novel terminal for mercury vapor apparatus and are concerned with certain details of construction which will be described later on.

The improvements are especially applicable to so-called quartz lamps.

The drawings show, in Figure 1, a portion of a quartz lamp having my invention applied thereto, the lamp, however, being shown in the process of manufacture; while Fi 2 shows a completed lampterminal.

The lamp, in practice, lies in a more or less inclined position, though, for convenience, the lamp end is here shown in a vertical position; and, for a like reason, mention will be made of the upper and the lower parts of the structure shown.

In the drawing, 1 is one end of a tube of quartz which, as a whole, constitutes the container of a mercury vapor quartz lamp.

It is well known that a perfect seal can not be obtained between platinum and quartz directly. Accordingly, since the way was pointed out by Mr. Kraus and myself, it has become customary to interpose between the quartz and the platinum oneor more intermediate zones or layers of heat resisting glass at the very extremity of the quartz tube and generally all the luminous column wherein the major part of the heat is developed. In the present instance I provide such an end piece, 2, of glass which is sealed at 3 to the quartz tube 1, and generally cup shaped and provided with a boss or thimble, 4, of the same material as the Specification of Letters Patent.

Patented Nov. 2, 1915. Renewed May 1, 1915. Serial No. 25,307.

l, is a yielding layer, 10, preferably of pulverulent material having a greater natural afiinity for mercury than platinum has. This material may be powdered copper or powdered aluminium, for example, and its function is to prevent the platinum tube from being amalgamated by the mercury which may pass down in vapor form or otherwise into the space or chamber containing the powdered material. This it does by itself being amalgamated and thus taking up the mercury which might affect the platinum tube. Between the layer, 10, and the frit, 9, is a barrier, 11, of ferric oxid, for example. At 12 the tube 1 is rounded out to a larger diameter, thus forming an annular cavity and the frit, 9, is made to fit and fill the tube at this point whereby any tendency to displacement of the parts is avoided. The object of the barrier is to prevent difiusion of mercury to the end of the structure whereby the platinum tube, 6, might be exposed to needless danger of amalgamation. The tube, 6, is so related to the core, 7, as to permit a slight play of the core within the tube, which is also true with regard to the quartz sleeve and the core, although the fit of the quartz tube is quite close and permits a small amount of play under variations of temperature of the core 7. This prevents the mercury forming the electrode from passing down freely within the sleeve 8, while at the same time preventing the natural shifting due to temperature change of the cores longitudinal part during the operation of the lamp.

At the extreme end of the terminal is an iron protecting cap, 13, so constructed as to provide an enlarged tubular portion freely surrounding the boss or thimble 4 and a narrower portion through which, at that stage of the manufacture which is illustrated in Fig. 1, both the tube 6 and the core part 2 and integral therewith. A central opening, 5, in the boss or thimble 4 is concentric with the tube 1 and also with a platinum tubular lead, 6, which is sealed hermetically to the inside of the boss or thimble. lVithin the tube, 6, is a core, 7, which is surrounded near its upper end by a tube, 8,

7 project slightly, at least so far as to be coterminous with the outer end of the cap. The three elements named, to wit, the cap, the tube and the core are welded together at the lower end of the device by an oxyacetylene flame and when they reach final fusion present a practically smooth and uninterof quartz. Surrounding the tube of quartz rupted surface, as shown in Fig. 2, whereby and, incidentally, the core 7, is a mass, 9, of the danger of breakage at this point is made frit which may consist, for example, of as small as possible and a convenient termi- 5 powdered silica and sodium silicate. Outnal is provided. In the second figure of the drawing the welded end described above is shown in full lines at the lower extremity of the figure.

The external circuit may be connected to the cap 13 and thus to the core of the platinum tube by fusing or constructing a conducting Wire, 14, to any convenient portion of the lamp.

I claim as my invention:

1. A terminal for mercury vapor apparatus comprising a boss or thimble of heat resisting material, a tube of platinum sealed inside the said thimble, a metal core Within the platinum tube and a cap fitting around the thimble and Welded to the outer ends of the tube and its core.

2. A terminal for mercury vapor apparatus comprising a tube of platinum, a boss or thimble of heat resisting glass Within which the platinum tube is sealed, an iron core Within the platinum tube and a cap embracing the sleeve and surrounding the ends of the conducting elements named.

3. A terminal for mercury vapor apparatus comprising a tube of platinum, a boss or thimble of heat resisting glass Within Which the platinum tube is sealed, an iron core within the platinum tube and a cap embracing the sleeve and surrounding the ends of the conducting elements named, the cap, tube and core being Welded together.

4. A terminal for mercury vapor apparatus comprising a tube of platinum, a boss or thimble of heat resisting glass within which the platinum tube is sealed, an iron terial' having a high degree of aflinity for mercury, a barrier of non-conducting material, such as ferric oxid, a frit of granular non-conducting material beyond the barrier and means for retaining the frit in place and a sleeve of quartz surrounding a continuation of the core and forming a substantially tight fit around the same.

6. In a terminal for mercury vapor apparatus, a platinum tube sealed through the end of the apparatus, the core for the said tube surrounded by a non conducting layer or layers impervious to mercury under ordinary pressures anda powdered conducting material surrounding the tube, said material having a highdegree of afiinity for mercury.

Signed at New York in the county of New York and State of New York this 7th day of January A. D; 1914.

FREDERICK G.- KEYES.

Witnesses:

WM. H. CAPEL, THOS. H, BROWN. I 

